Device for automatically changing tools

ABSTRACT

A device for automatically changing tools which can be used with a machine which has at least one substantially horizontal tool holder, the device including a transfer mechanism for transferring the tools from a tool holder to a magazine, and having a clamp with jaws which are capable of gripping and holding a flange projecting from the tool, and which, while the machine is in operation, are open and located on opposite sides of the flange of the tool mounted in the tool holder, the tool having a projecting main plate, which is of the same shape as the flange and which is so arranged in front of the flange that it defines with the latter an opening into which a jaw of the clamp can enter, the main plate being located when a tool is mounted in the tool holder in the same plane as a pair of plates on the holder to form a protector against the penetration of shavings between the flange and the jaws of the clamp.

United States Patent 1191 Pegard Feb. 5, 1974 [5 DEVICE FORAUTOMATICALLY 2,619,357 11/1952 Montgomery 279 1 ME CHANGING TOOLS2,711,904 6/1955 Gardner et a1 279/1 ME 3,524,248 8/1970 Durr et a1.29/568 Inventor: Pierre Pegard, Courbevoie, France Ateliers G.S.P.(Guillemin, Sergot, Pegard), Courbevoie, France Filed: Aug. 24, 1971Appl. No.: 174,314

Assignee:

Foreign Application Priority Data Sept. 3, 1970 France 7032105References Cited UNITED STATES PATENTS 7/1970 Trebble 29/568 10/1967Hosca 29/568 3/1972 Perry et al. 5/1945 7/1945 Hite 279/1 ME PrimaryExaminer-Andrew R. Juhasz Assistant Examiner-7.. R. Bilinsky 5 7ABSTRACT which is of the same shape as the flange and which is soarranged in front of the flange that it defines with the latter anopening into which a jaw of the clamp can enter, the main plate beinglocated when a tool is mounted in the tool holder in the same plane as apair of plates on the holder to form a protector against the penetrationof shavings between the flange and the jaws of the clamp.

7 Claims, 10 Drawing Figures Patented Feb. 5, 1974 5 Sheets-Sheet lPatented Feb. 5, 1974 3,789,472

5 Sheets-Sheet! Patented Feb. 5, 1974 3,789,472

5 Sheets-Sheet 5 DEVICE FOR AUTOMATICALLY CHANGING TOOLS The presentinvention relates to devices for automatically changing tools for usewith machines having at least one substantially horizontal tool holder,such as a driven spindle and to the adaptation of such devices tomachines for performing the noted function.

Some known devices utilize a rotary magazine having a horizontal axisand are positioned distant from the machine, necessitating therebycomplex transfer manipulation of the tools between the magazine and thedrive spindle of the machine. Accordingly, transfer machanisms presentlyused are of complex construction and require extensive maintenance;moreover, the dead time required for changing tools is relatively high,and consequently, the cost of the machining operation is quite high.

Other known devices have their magazines located close to the machinedrive spindle and are mounted on the machine head for movementtherewith. Tool transfer is thus simplified and time for transfer isalso shortened. However the tools stored in the magazine are lengthy,hindering thereby the approach of the work piece to be machined to thedrive spindle of the machine. Also, the number of tools which can beplaced in reserve in such magazine is limited.

The aim of the invention is to avoid the shortcomings of the describedprior devices while incorporating some of the advantageous featuresthereof;

a. by supporting the magazine other than on the machine head so thatmachine operation will not be interfered with,

b. by assuring integrity of operation,

c. by increasing the number of tools which can be held in reserve,

d, by assuring free access between the workpiece to be machined and thetool for machining thereof,

e. by arranging the axis of rotation of the magazine vertically so thattools received in slots of the magazine are readily supported andaccurately indexed during rotation of the magazine, and

f. by simplifying the construction and arrangement of the transfermechanism as well as its programmed control device.

The transfer mechanism construction is simplified because it is operatedunder control of simple longitudinal movements. Hence, the speed ofoperation may be very high and dead time small. Moreover, the controlsequence is simple and therefore susceptible to programming, Finally,the mechanism is characterized by very high reliability making fortrouble-free operation.

Simplification of the structure of the transfer mechanism also resultsfrom the disposition of the tool gripping clamp and from the design ofatilt effecting mechanism enabling the tool to be tilted from ahorizontal to a vertical position and vice versa. In the inoperativeposition of the clamp, which is close to the operating tool, the clampis open but within ready reach of the tool. thereby ensuring faster toolchange and reduced dead" time. As regards the tilt effecting mechanism,by utilizing a cam for transforming a part of the longitudinal movementinto a pivotal movement enables the mechanism to be operated with asingle longitudinal feed device without reducing the transfer speed andwith one sequence of the program omitted.

The invention also aims to reduce magazine bulki- ,ness for a givenstorage handling capacity. This is achieved by reducing the flange sizeof the tools which cooperate with the gripping clamp. As a result thewidth of the slots defining storage spaces in the magazine can bereduced.

Finally the invention aims to prevent entry of chips between the flangeof the operating tool and the clamp in the inoperative position of theclamp since such chips would find their way to and damage the toolgripping clamp. This is true because the clamp in its open positionstraddles the flange of the tool which is rotating and hence any chipsentering between the rotating flange and the relatively fixed jaws mayscar the flange and the clamp surfaces.

In the device according to the invention, each tool has, between itsmachining end and its tool gripping end and/or on the drive spindle ofthe device, the aforementioned flange which is of small width. Thetransfer mechanism for transferring the tools from the machine drivespindle, forming the toolholder, to the magazine comprises asaforementioned a clamp, the jaws of which are no larger than flanges ofthe tool to be gripped, this clamp when open being positioned in such amanner that its jaws are spaced from and located on opposite sides ofthe flange of the tool, while held by the drive spindle toolholder. Eachtool is provided with a main plate similarly shaped as the flange andarranged in front of and defining with the latter a restricted spaceinto which the front fixed jaw of the clamp enters. The drive spindletool holder is provided with two auxiliary plates which, when therelevant tool is mounted to the tool holder, are disposed in the sameplane as the main plate and to either side thereof to form therewith acircular protector preventing penetration of chips between the flange ofthe tool and the jaws of the clamp.

According to one particularly advantageous embodiment, the tool transfermechanism comprises, where the slots in the magazine are provided forholding the tools along a substantially vertical axis, at least onesliding member which, on the one hand, is guided for movement parallelto the drive shaft along a support for the head of the tool holder driveshaft, and which, on the other hand, is connected to a longitudinallyoperating feed member, the clamp being mounted to pivot on the slidingmember about an axis at right angles to the longitudinal axis ofmovement of the sliding member and connected to a positive tiltingdevice bearing on the support.

Preferably, the positive tilting device comprises at least one guidedmember and at least one guiding member, the former being supported bythe sliding member and the latter by the support, the guiding memberhaving a cam profile close to the tool holder, in order to producepivoting action of the clamp during longitudinal movement of the slidingmember, and a rectilinear part close to the magazine and parallel to thelongitudinal axis to assure retention of the tool gripped by the clampin vertical position.

Advantageously, the aforementioned support is a second sliding memberguided for movement parallel to the first along a carriage fixed to thehead of the tool holder drive shaft, this second sliding member beingactuable by a hydraulically operated feed member.

Various additional features and advantages of the invention will beapparent from the detailed description which follows.

One embodiment of the invention will now be described, by way of anon-limiting example, with reference to the accompanying drawing inwhich:

FIG. 1 is a diagrammatic side elevation of a machine fitted with adevice for automatically changing tools,

FIG. 2 is a top plan view of the arrangement of FIG.

FIG. 3 is an elevation partly in section and to a much larger scale ofthe transfer mechanism shown in FIG. 1,

FIG. 4 is a part vertical section through the longitudinal axis of thetransfer mechanism shown in FIG. 3 and to a scale larger than FIG. 3 andshowing the clampof the transfer mechanism and its connection to themovable carriages,

FIGS. 5 and 6 are cross-sections taken along the lines VV and Vl-VIrespectively of FIG. 4,

FIG. 7 is a view similar to FIG. 4 and shows the guard for the toolflange and clamp, and

FIGS. 8-10 are cross-sections taken along the lines VIII-VIII to X-X ofFIG. 7.

The machine shown by way of example in FIGS. 1-3 is intended for useprimarily in milling, reaming, boring or tapping operations. I

It comprises a fixed frame 1 having a bed 2 supporting a table 5orthogonally adjustably movable in a horizontal plane. The work piece tobe machined is fixed to table 5.

The frame 1 is also integral with an upright 6 located at the rear ofthe bed 2, having a vertical slide 7 for directly guiding a head 8adapted to receive a tool holder drive spindle.

A tool holder 9 in the form of a drive spindle is mounted for rotationabout and for longitudinal sliding movement in the head along ahorizontal axis 10. The tool holder 9 is at a vertical position (FIG. 1)on the slide 7 enabling a tool 11 positioned in the holder to be storedin a magazine upon transferring the tool positioned in the holder to themagazine by means described in greater detail hereinafter. After thetool in the holder is transferred to the magazine another tool isremoved from the magazine and positioned in the tool holder forperforming a further operation on a work piece.

The magazine 12 is shown in FIGS. 1-3 comprises a circular groved ornotched wheel 13 having a vertical axis 14 about which it is adapted tobe rotatably driven. To this end, the wheel 13 is carried by a drum 15which caps the upper end of column 16, integrally formed with the frame1, the column, as seen in FIG. 1, being behind upright 6. An inner hub17 of the drum 15 is provided, on the one hand, with coils wound on arod 18 fixed to the column 16 along the axis 14 and, on the other hand,with gear teeth 19 meshing with pinion 20, operated by a suitable drive,not shown.

Whatever the method of assembly and feed of the wheel 13, it isessential for the described embodiment that the latter and the tools 11have the following features:

each tool 11 should comprise an annular support or bearing part 21 (FIG.7) between its forward machining part 22 (mill, drill, reamer, tap.....)and its rearward part 23 which is held in the tool holder 9;

the wheel 13 is to be provided with peripheral notches 24 (FIG. 2) whichhave outwardly facing openings, the width of which is substantiallyequal to the diameter of part 23 immediately behind the bearing part 21of the individual tools (FIG. 7); thus each notch constitutes a meansfor receiving and storing. a vertically disposed tool within a notch,the tool part 23 being supported by its bearing part 21 resting on theedge defining the notch;

the specific notch 24s (FIG. 2) selected for either extracting a tooltherefrom or for storing a tool therein is determined by rotation ofwheel 13 under control of a programmer, the notch selected being in theplane of movement of the transfer mechanism as hereinafter described.

Any suitable type of magazine can be used with the proviso that theselected notch 24s be brought into the operational position (FIG. 2)i.e. the position in which it receives or makes available a tool.Accordingly, the axis of rotation of the wheel 13 of magazine 12 shouldbe perpendicular to the axis of the spindle of the tool holder 9. Underthese circumstances, the magazine may have a chain drive, slide drum orthe like, for moving the stored tools along a closed or an open circuit;i.e. curvilinear or rectilinear, and one or more drive stages may beused. The disclosed embodiment using the rotating wheel 13 is preferredin view of its simple design and economy of manufacture.

The automatic tool changing device in accordance with the inventioncomprises, in addition to the magazine 12, a transfer mechanism 25which, as is seen in FIGS. 1 and 3, is mounted on the head 8 of the toolholder drive spindle for movement therewith. The transfer mechanism inturn comprises a clamp 26 and a transfer effecting operating device 27.

Th clamp 26, as will be seen in FIG. 4, cooperates with a grippingflange 28, affixed by suitable means to part 23 of each tool 11, nearthe support or bearing part 21 of the tool (FIGS. 4 and 7). In theillustrated embodiment, the clamp 26 comprises a fixed jaw 29 (FIG. 4)supported by the operating device 27, and a movable jaw 30longitudinally displaceable with respect to the fixed jaw. The fixed jawis located on the operative front end portion or machining part 22 ofthe tool 11 and is provided with a nose extension 31, preferably flat,designed to engage the front face 32 of the flange 28 (FIG. 4). Themovable jaw 30 is provided with a nose extension 33 having a V-shapedprojecting portion 34, which is movable longitudinally parallel to theaxis of the tool (FIGS. 4, 7 and 10). The guide portion 34 is designedto enter, during closure of the clamp, a complementary shaped, archedgroove 35 provided in the rear face of the flange 28 (FIGS. 4, 7, and8).

Providing the clamp open position during a machining operation is ofimportance in simplifying the design of device 27. In the open orinoperative position of the clamp, shown in FIG. 3, the clamp parts aredisengaged from flange 28 and nose extensions 31 and 33 of jaws 29 and30 are spaced from the opposite sides of the a tool to and from holder 9from and to the selected notch 24s of the magazine 12. All that isrequired is an initial forward movement of the clamp,-followed by anupward pivotal movement of the clamp about an axis perpendicular to aplane containing axes 10 and 14. (see F IG. 1). The initial forwardmovement extracts the tool from the holder and the pivotal movementholds it in a vertical position. With the tool held by the clamp invertical position the clamp is moved rearwardly parallel to the axis ofthe tool holder spindle to position the extracted tool in theappropriate programmer selected notch 24s. The movements of theoperating device 27 are reversed for mounting a new tool from themagazine in the holder.

In the embodiment described, the wheel 13 is preferably located abovethe head 8 of the tool holder spindle, when the head is in the mid-levelposition shown in FIG. 1, a distance above the operating device 27 equalto the upward pivotal displacement of the support or bearing part 21 ofthe tool, while held by the clamp 26 during pivotal movement of thelatter following its forward movement by the transfer mechanism 25, sothat the support or bearing part 21 will rest on the rim of the notch,which receives the tool.

Obviously, the magazine 12 can be aligned with the tool transfermechanism 25 by either vertically moving the head 8 of the tool holderspindle, in which case the level of the magazine would be fixed, or themagazine can be vertically displaced in which event the device producingits displacement would be controlled by a programmer to ensure that themagazine returns to the selected tool transfer or receiving level beforethe end of a machining operation.

. The description which follows with reference to FIGS. 3-6 of thedrawing, is directed to a particularly advantageous, non-limitingembodiment of the clamp 26 and its operating device 27. The structure tobe described provides the pivotal and longitudinal movements of the toolabove referred to. Initial longitudinal movement in a forward directionbefore effecting pivotal movement, facilitates extraction of the toolfrom the holder.

The operating device 27 comprises two slides 36 and 37 mounted in seriesand movable parallel to the axis 10 of the tool holder 9.

The lower slide 36 is guided along a carriage 38 of the head 8 of thetool holder drive spindle (FIGS. 4 and 6). It bears the cylinder 39 of apressure operated actuating means, including a piston rod 41, fixed to afront angle plate 42 of the head 8 (FIGS. 3 and 4) and a piston 43 whichdivides the cylinder into two chambers 44 and 45 (FIG. 3).

The upper slide 37 is guided along a carriage 46 forming part of thelower slide 36 (FIG. 6), which should be over the head 8. It is attachedto a pressure operated actuating device 47, bearing on the lower slide(FIG. 6).

In the embodiment shown (FIGS. 3 and 4), the lower slide 36 also carriesthe cylinder 48 of a pressure operated actuating means including pistonrod 49 fixed to a rear plate 50 on the upper slide 37 and piston 51which divides the cylinder 48 into two chambers 52 and 53.

The chambers 44 and 43 and the chambers 52 and 53 of the respectivepressure operated actuating means can be connected selectively by adistributor (not shown) to a hydraulic circuit under pressure and to areturn circuit, this distributor being operated under the control of theaforementioned programmer.

As is clearly apparent from FIGS. 4-6, the fixed jaw 29 of the clamp 26is integral with side lugs 54 arranged between the flanges 55 of theupper slide 37. The hydraulic pressure applying means when actuatedapplies pressure to slide 37. The flanges 55 support axles 56 aboutwhich the lugs 54 and, consequently, the clamp 26 are able to pivot.

Moreover, as is further apparent from FIGS. 4-6, the fixed jaw 29 of theclamp is connected to two other lugs 57 arranged between the front sidewalls of the lower slide 36, the hydraulic pressure applying means 40when actuated operating the slide 36. Each lug 57 carries an idler wheel58 received in a guide groove 59 formed in the inside wall of the lowerslide 36.

The articulation of the fixed jaw of clamp 26, with the structuredescribed, will be about the aligned axles 56 of the upper slide 37 andthe guiding of its wheels 58, in the grooves 59 of the lower slide 36,is intended, on the one hand, to ensure pivoting of said clamp aboutaxles 56 when the upper slide 37 is moved longitudinally by thehydraulic pressure applying means 47 relatively to the lower slide 36and, on the other hand, to hold the tool carried by this clampvertically as the longitudinal movement is continued.

To this end, the aligned axles 56 are situated above the wheels 58 whenthe clamp is in its inoperative position (FIG. 3) and also at the end offorward longitudinal movement of the tool in the operative position ofthe clamp. Moreover, each groove 59 has at its front end portion anascending curved'cam profile portion 60, which effects pivoting of theclamp and, behind the cam profile, a rectilinear portion 61 parallel tothe axis 10 of the tool holder 9, to ensure retention of the clamp inits vertical position in which it is disposed by said pivoting action.As regards the clamp 26, FIG. 4 clearly shows that its movable jaw 30includes a cylindrical member guided in a bore 62 of the fixed jaw 29,the nose 33, which passes through an elongated aperture 63 preventinglateral pivoting of the nose, being integrally formed with thecylindrical member.

The cylindrical member has integrally formed therewith a piston 64mounted for reciprocation in a cylindrical cut-out 65 formed in thefixed jaw 29. The piston 64 defines with a rear wall defining thecylindrical cutout, a rotary coupling 68 and piping (not shown) to thedistributor above referred to. The hydraulic fluid arriving underpressure in the chamber 66 acts to close the clamp by moving the nose 33towards the fixed jaw 31. The piston 64 is, moreover, subjected at itsopposing face, to the counterforce of a spring 69 resting on a shoulderof the fixed jaw and tending to urge the clamp to its open position.

The operating piston 64 cooperates with a positively acting lockingmember during the closing movement of the clamp. This member is formed,in the embodiment shown, by at least one ball 70 arranged in a hole 71in the piston 64 with freedom of movement with the piston and relativethereto in a radial direction. The ball 70 is intended to project eitherinto a recess 72 in the fixed jaw 29 so as to lock the said piston 64when the nose portions 31 and 33 engage the flange 28, or into a secondrecess 73 formed between a bore 74 of the piston 64 and a reduced wallportion of a secondary piston 75 disposed for axial reciprocation inbore 74.

The second piston 75 separates the bore 74 into two chambers 76 and 77.The chamber 76 is connected by a conduit 78 to the rotary coupling 68and through piping (not shown) to the aforementioned distributor. Thechamber 77 on the other hand, is open to the atmosphere and contains aspring 79 counteracting forward movement of the piston 75.

When the distributor connects the chamber 66 to the circuit underpressure in order to effect closure of the clamp, it simultaneouslyconnects the chamber 76 to the return circuit. Consequently, the piston64 moves in the direction of the arrow F while the spring 79 urges thepiston 75 in the opposite direction; the inclined ramp 80 defined by thereduced wall portion of piston 75 acts on the ball 70 and forces theball into the recess 72 as soon as the piston 64 has reached the end ofits stroke; the piston 75 no longer being restrained by the ball once itenters recess 72, continues its stroke and covers the hole 71, thuspreventing withdrawal of the said ball and unlocking of the clamp.

When the distributor connects the chamber 76 to the circuit underpressure and the chamber 66 to the return circuit, it causes the clampto be opened. This results because the piston 75, when subjected topressure, moves in the direction of the arrow F. When the piston 75 ismoved sufficiently forward so that the inclined ramp 81 of piston 75uncovers the opening 71 and is in alignment with the ball in recess 72,the ball is free to move into recess 73 at which time the piston 64 isfree to move rearwardly under the influence of spring 69 and carryingwith it the movable nose 33 for separation from the fixed nose 31.

The changing of a tool is effected in the following manner:

On the completion of a machining operation, the tool holder 9 is stoppedand the work piece is moved away therefrom.

The clamp 26 is spaced from both sides of the flange of the tool at thisstage and the operating device 27 is in the position shown in FIG. 3.

The programmer simultaneously controls, on the one hand, the rotation ofthe magazine 12 so as to bring the selected notch 24s into coincidencewith the plane containing axes 10, 14 and on the other hand, the.vertical movement of the head 8 of the tool holder drive spindle so asto bring it to a level suitable for storing the tool in the magazine.

At the same time as these movements are made, the programmer controlsthe loosening of the tool by either causing rotation of a screw or theopening of a clamp, such screw or clamp extending coaxially into thehollow drive spindle of the tool holder 9 for engaging the rear end ofpart 23 of the tool. Simultaneously, the programmer operates to controlthe hydraulic pressure applying means 66, 67, pistons 64, 75 whichoperate in conjunction with ball 72 to lock the clamp 26 over the flangeof the tool.

The tool now being gripped by the clamp 26, the programmer then controlsthe hydraulic distributor in order to supply the operating device 27 inaccordance with the sequences referred to below referring. primarily toFIGS. 3 and 4:

the chamber 44 is connected to the circuit under pressure and thechamber 45 is connected to the return circuit, whilst the chambers 52and 53 remain isolated. The upper hydraulic pressure applying means 47.thereby links the slides 36 and 37 and the lower hydraulic pressuremeans 40 moves the latter longitudinally in the direction of the arrowF, the clamp 26 remaining in its horizontal position. The tool 11 isthereby extracted from the tool holder-9 (FIG. 7).

When the assembly of the slides reaches the end of the forward travel,the chambers 44 and 45 of the pressure applying means 40 are isolated,and the chamber 52 is connected to the circuit under pressure and thechamber 53 to the return circuit. The upper slide 37 will now bedisplaced by the upper hydraulic pressure applying means 47 and will bemoved longitudinally in a direction opposite to that of the arrow F, thelower slide remaining immobile. The grooves 59 being fixed and the axles56 being moved rearward, the clamp 26 will be caused to pivot in thedirection of the arrow F by virtue of. wheels 58 being constrained tomovement in the curved part 59 of the grooves which are provided with acam profile for this purpose. The clamp when so pivoted will move thetool from a horizontal to a vertical position and when the wheelsapproach a rectilinear part 61 of the grooves merging with the camprofile portion, the clamp 26 will be constrained for movement with thetool in vertical orientation during rearward longitudinal movement ofthe clamp.

As soon as the upper slide 37 has reached the end of its rearwardtravel, the chambers 52 and 53 are isolated whilst the chamber 45 isconnected to the circuit under pressure and the chamber 44 to the returncircuit. The lower slide 36 will now move longitudinally in a directionopposite that of the arrow F and will carry with it the upper slide.Atthe end of its rearward travel, the clamp 26 passes under the wheel 130f the magazine and inserts the tool which it is carrying into theselected notch 24s by placing the bearing part 21 of this tool over theedge of the latter.

The programmer thus controls successively:

the opening of the clamp 26,

the rotation of the magazine 12 in order to bring it into coincidencewith the plane containing the axes 10, 14, the selection of a specifictool to be mounted in the holder by programmer selecting a predeterminednotch in the magazine; the clamp being open at this point will notinterfere with rotation of the magazine,

the clamp after selecting a tool is closed,

the connection of the chambers 44 and 45 of the lower hydraulic pressureapplying means 40 is reversed followed by connection of the chambers 52and 53 of the upper pressure applying means, in order to cause, first ofall the longitudinal advance of the clamp in the direction of the arrowF and at the end of such travel, pivoting of the clamp in a directionopposite to that of the arrow F,, the grooves 59 fulfilling the samefunction as before but in the reverse direction.

The tool held by the clamp is thus brought into the horizontal positionand located in front of the tool holder 9.

The programmer then controls the connection of the chamber 45 to thecircuit under pressure and that of the chamber 44 to the returncircuit-the chambers 52 and 53 being isolated in order to cause themovement of the assembly of the slides 36 and 37 in a direction oppositeto that of the arrow F. The handling part 23 of the tool enters the toolholder 9 and abuts the latter. The movement of the assembly of slides isthen stopped and the chambers 44 and 45 are isolated.

The programmer then controls, on the one hand, the

opening of the clamp 26, the movable nose 33 of which is separated fromthe flange 28 of the too] and, on the other hand, the screw or thelocking clamp in the holder of the tool, a protective flange 86 of whichis separated from the fixed nose 31 of the said clamp 26.

The cycle for changing the tool is then terminated and a new machiningoperation can be commenced.

Where the horizontal travel of the clamp between the tool holder andmagazine is not too extensive and where the extraction of the tool fromthe holder can be achieved by a simple pivotal movement, the lower slide36 and its associated pressure applying means 40 can be omitted. Thegroove or grooves 59 will then be formed in a support integral with thehead 8 of the tool holder drive spindle, this support also being usablefor guiding the upper slide 37 in its movement and the attachment of itshydraulic fluid pressure applying means 47. Obviously, the forwardlongitudinal movement which precedes pivoting movement of the clampwould be omitted.

It has been shown hereinbefore that during a maching operation in a workpiece, it is essential to maintain the clamp 26 open on both sides ofthe flange 28 of the tool mounted in the holder 9.

It is also essential to reduce the size of the magazine 12 for a givennumber of tools placed in reserve and to increase this capacity for agiven size. To this end, the flange 28 as is apparent from FIG. 8, istruncated along two edges 82 which are parallel and equidistant from theplane (10,14), the width lof this flange thus becoming at most equal tothe diameter d of the bearing part 21. Consequently, a tool may bestored in the magazine at distances d around the circumference of themagazine although the outer diameter D of each flange of the tool isvery much larger so that it can project from the magazine and may thusbe gripped by the clamp 26.

Moreover, as the clamp 26 surrounds the flange 28 and remains in placewhile th tool rotates, there is a possibility of shearing occuringbetween the flat edges 82 of this rotating flange and the edges 83 ofthe jaws 31 and 33 of the fixed clamp. Also, cuttings i.e. chips,shavings, etc. produced by the tool during a machining operationreaching tthis area could jam between the clamp and the flange. Thiswould damage the clamp and the flange.

To avoid the possibility of cuttings finding their way between the clampand the flange, a chip shield is provided as shown in FIGS. 7-10.

The shield as protector comprises a main plate 84 on each tool of thesame shape as theflange 28. It is connected to the flange in spacedrelation thereto, to define a neck portion 85 enabling the free passageof the nose 31 of the clamp when the tool is rotating or is movingaxially during the locking thereof.

The shield also comprises a pair of plates 86 fixed to the tool holderas shown in FIG. 7. When a tool is mounted in operative position in thisholder, the plates 86 are located in the same plane as the main plate 84and complement its shape so that the assembly of plates 84, 86 defines acircular disc covering not only the flange 28 of the tool, but also theparts of the noses 31 and 33 of the clamp which grip it.

Thus the shield assembly 84, 86 shields the cuttings from entering thespace between the clamp and the flange.

In the embodiment shown, the plate 84 is centered on an annular boss 87of the flange 28 and secured to the I of the tool, coupled to the latterby means of cotters 91 and restricted against axial movement by a splitring 92.

The shield plates 86 are integral with cylindrical sectors 93 applied toa cylindrical extension 94 of the tool holder 9 and fixed thereto bymeans of screws 95.

The extension 94 is provided with tongues 96 for driving the tool inrotation, these tongues cooperating with radial grooves 97 in the flange28.

The device of the invention can be used with automatic or semi-automaticmachine tools having at least one machining tool holder, especiallyhorizontally disposed, and which are operated under programmer control.

Although the invention has been described with reference to particularembodiments it will be understood that it is not to be limited theretoand that variations and modifications may be made within the scope ofappended claims.

I claim:

1. A machine comprising a substantially horizontal tool holder having apair of protector plates fixed to the -tool holder, said tool holderbeing operable with tools adapted to be stored in a magazine, at leastone tool having a projecting flange extending in a plane transversely tothe longitudinal extent of the tool and a projecting main plate ofsubstantially the same shape as the flange, a transfer mechanism fortransferring said tool to said tool holder from a magazine and viceversa, a clamp formation on the transfer mechanism, said clamp formationhaving jaws for gripping and holding the tool projecting flange, meansforming part of the transfer mechanism for moving said jaws, with thetool operatively mounted in the tool holder, to an open po sitionwherein said jaws are located on each side of the tool flange, said mainplate being shaped and positioned adjacent relative to said tool flangeto define with the latter a laterally open-ended annular recess intowhich one of the jaws of the clamp enters and being further positionedin the same plane as and relative to the two protector plates, when thetool is in the operating position in the holder, to form a shieldagainst entry of tool cuttings between the tool flange and the clampjaw.

2. A machine according to claim 1, including a magazine operativelyassociated with said transfer mechanism and being formed with notchesfor receiving from said transfer mechanism tools for positioning thereinalong a vertical axis, a tool holder head, a support mounted on thehead, said transfer mechanism including at least one sliding membermounted for movement aiong the support parallel to the tool holder,means connected to said sliding member for driving the same inlongitudinal direction, first means mounting the clamp formation to thetransfer mechanism for pivotal movement of the clamp about an axisperpendicular to the longitudinal movement of the sliding member, andmeans for pivoting said clamp about said axis perpendicular to thelongitudinal movement of the sliding member.

3. A machine according to claim 2, including a second sliding member, aslide-way fixed to the tool holder head for guiding the second slidingmember parallel to the first, and means connected to the second memberfor longitudinal reciprocation thereof.

4. A machine according to claim 1, wherein said last- 4 named meansincludes at least one guided member and at least one guide member, oneof said members being carried by the sliding member and the other by thesupport, a cam profile part on the guide member cooperating with saidguided member for providing said pivotal movement of the clamp duringinitial longitudinal movement of the sliding member to orient said toolfrom a horizontal to a vertical position, a rectilinear part of thesliding member merging with said cam profile part and extending parallelto the longitudinal axis of the tool holder in the direction of themagazine.

5. A machine according to claim 1, wherein one of the pair of jaws ismovable and the other fixed, the fixed jaw being formed with acylindrical opening, a first piston carried by the movable jaw andmounted to slide in the cylindrical opening in the fixed jaw, a secondpiston mounted to slide in a bore formed in the first piston, the secondpiston and the cylinder wall defining the cylindrical opening havingrecessed portions, at least one laterally movable locking member heldcaptive by the first piston and selectively projecting into saidrecesses as a function of the relative movement of said first and secondpistons, said locking member serving to lock said first piston when insaid recess in said cylinder wall and when engaged by the peripheralwall of the second piston, and means for moving said second pistonagainst the action of a spring for freeing said locking member from itslocked position to permit movement of the first piston, against theaction of a second spring, in opposition to the second piston, wherebyto unlock the clamp.

6. A machine according tto claim 5, wherein said transfer mechanismcomprises a first sliding member, the fixed jaw of the clamp beingcarried by the first sliding member and being provided with a projectingpart engaging one face of the tool flange, and a projecting part on themovable jaw having a V-shaped extension which seats in a complementarygroove formed in the opposite face of said tool flange.

7. A tool machine comprising a substantially horizontally disposedrotary tool holder adapted to carry a tool for rotation thereby about anaxis, a storage magazine spaced from said tool holder for receiving andmaking available one of a series of tools to be stored thereby, eachsaid tool having a projecting flange extending transversely to thelongitudinal extent of the tool, a transfer-mechanism disposed foroperation between said tool holder and said magazine and having a clampformation defined bya pair of jaws disposed in straddling relation tosaid tool projecting flange, said jaws being relatively movable betweena first position thereof in which they grip the flange and a secondposition in which they are spaced from the flange, said transfermechanism including means for moving said jaws to said first and secondpositions, said transfer mechanism further including means for moving'said tool, from said tool holder, gripped by said jaws in a firstorientation and then to said magazine gripped by said jaws in a secondorientation perpendicular to the first, a main plate for each tool ofthe same shape as said flange, said main plate being fixed adjacent saidprojecting flange and being rebated at its outer extremities to definein the rebated region a space between said flange and said main plate,one of the jaws being received in said space, and a pair of protectorplates on the tool holder which in the operative position of the tool inthe tool holder compliment the shape of the main plate to definetherewith an annular shield which intersects the axis of rotation forpreventing entry of tool cuttings between the tool flange and the clamp

1. A machine comprising a substantially horizontal tool holder having apair of protector plates fixed to the tool holder, said tool holderbeing operable with tools adapted to be stored in a magazine, at leastone tool having a projecting flange extending in a plane transversely tothe longitudinal extent of the tool and a projecting main plate ofsubstantially the same shape as the flange, a transfer mechanism fortransferring said tool to said tool holder from a magazine and viceversa, a clamp formation on the transfer mechanism, said clamp formationhaving jaws for gripping and holding the tool projecting flange, meansforming part of the transfer mechanism for moving said jaws, with thetool operatively mounted in the tool holder, to an open position whereinsaid jaws are located on each side of the tool flange, said main platebeing shaped and positioned adjacent relative to said tool flange todefine with the latter a laterally open-ended annular recess into whichone of the jaws of the clamp enters and being further positioned in thesame plane as and relative to the two protector plates, when the tool isin the operating position in the holder, to form a shield against entryof tool cuttings between the tool flange and the clamp jaw.
 2. A machineaccording to claim 1, including a magazine operatively associated withsaid transfer mechanism and being formed with notches for receiving fromsaid transfer mechanism tools for positioning therein along a verticalaxis, a tool holder head, a support mounted on the head, said transfermechanism including at least one sliding member mounted for movementalong the support parallel to the tool holder, means connected to saidsliding member for driving the same in longitudinal direction, firstmeans mounting the clamp formation to the transfer mechanism for pivotalmovement of the clamp about an axis perpendicular to the longitudinalmovement of the sliding member, and means for pivoting said clamp aboutsaid axis perpendicular to the longitudinal movement of the slidingmember.
 3. A machine according to claim 2, including a second slidingmember, a slide-way fixed to the tool holder head for guiding the secondsliding member parallel to the first, and means connected to the secondmember for longitudinal reciprocation thereof.
 4. A machine according toclaim 1, wherein said last-named means includes at least one guidedmember and at least one guide member, one of said members being carriedby the sliding member and the other by the support, a cam profile parton the guide member cooperating with said guided member for providingsaid pivotal movement of the clamp during initial longitudinal movementof the sliding member to orient said tool from a horizontal to avertical posItion, a rectilinear part of the sliding member merging withsaid cam profile part and extending parallel to the longitudinal axis ofthe tool holder in the direction of the magazine.
 5. A machine accordingto claim 1, wherein one of the pair of jaws is movable and the otherfixed, the fixed jaw being formed with a cylindrical opening, a firstpiston carried by the movable jaw and mounted to slide in thecylindrical opening in the fixed jaw, a second piston mounted to slidein a bore formed in the first piston, the second piston and the cylinderwall defining the cylindrical opening having recessed portions, at leastone laterally movable locking member held captive by the first pistonand selectively projecting into said recesses as a function of therelative movement of said first and second pistons, said locking memberserving to lock said first piston when in said recess in said cylinderwall and when engaged by the peripheral wall of the second piston, andmeans for moving said second piston against the action of a spring forfreeing said locking member from its locked position to permit movementof the first piston, against the action of a second spring, inopposition to the second piston, whereby to unlock the clamp.
 6. Amachine according tto claim 5, wherein said transfer mechanism comprisesa first sliding member, the fixed jaw of the clamp being carried by thefirst sliding member and being provided with a projecting part engagingone face of the tool flange, and a projecting part on the movable jawhaving a V-shaped extension which seats in a complementary groove formedin the opposite face of said tool flange.
 7. A tool machine comprising asubstantially horizontally disposed rotary tool holder adapted to carrya tool for rotation thereby about an axis, a storage magazine spacedfrom said tool holder for receiving and making available one of a seriesof tools to be stored thereby, each said tool having a projecting flangeextending transversely to the longitudinal extent of the tool, atransfer mechanism disposed for operation between said tool holder andsaid magazine and having a clamp formation defined by a pair of jawsdisposed in straddling relation to said tool projecting flange, saidjaws being relatively movable between a first position thereof in whichthey grip the flange and a second position in which they are spaced fromthe flange, said transfer mechanism including means for moving said jawsto said first and second positions, said transfer mechanism furtherincluding means for moving said tool, from said tool holder, gripped bysaid jaws in a first orientation and then to said magazine gripped bysaid jaws in a second orientation perpendicular to the first, a mainplate for each tool of the same shape as said flange, said main platebeing fixed adjacent said projecting flange and being rebated at itsouter extremities to define in the rebated region a space between saidflange and said main plate, one of the jaws being received in saidspace, and a pair of protector plates on the tool holder which in theoperative position of the tool in the tool holder compliment the shapeof the main plate to define therewith an annular shield which intersectsthe axis of rotation for preventing entry of tool cuttings between thetool flange and the clamp jaw.